The current market's demands encourage manufacturers of consumer goods to create new decorative patterns on items and containers that would appeal to consumers. One of the desirable features of such decorative patterns typically includes insignia having a three-dimensional relief extending over the surface of the underlying surface. Such three-dimensional pattern can be accomplished by a variety of means, including printing. Various printing techniques known in the art include, e.g., offset printing, screen printing, photo printing, flexography, letterpress printing, jet printing, and others.
Silkscreen printing, for example, is a method of stencil print making in which a design is imposed on a screen of polyester or other fine mesh, with blank areas coated with an impermeable substance. Ink is forced into the mesh openings by the fill blade or squeegee and onto the printing surface during the squeegee stroke. Pad printing is a printing process that can transfer a 2-D image onto a 3-D object. This is accomplished using an indirect offset printing process that involves an image being transferred from the image plate via a silicone pad onto a substrate. Ink-jet printing is a type of digital printing that creates an image by propelling droplets of ink onto a substrate, such as, e.g., paper or plastic.
The use of expanding agents in inks is also known. For example, U.S. Pat. No. 3,615,972 describes thermoplastic microspheres that encapsulate a liquid blowing agent, wherein heating of the microspheres causes their expansion. U.S. Pat. No. 6,004,419 describes a heat-transfer printing sheet and a thermally-expandable ink layer formed thereon, comprising as an expanding agent a thermally-expandable micro-capsule containing easily volatilizable hydrocarbon and a binder resin. EP-A-0348372 describes a method and an apparatus for producing expanded thermoplastic microspheres without agglomerate formation. US 20120015162 is directed to a coated material, including a support, covered with at least one layer of polymer resin that includes heat-expandable microspheres. US 20110247749 is directed to a process for coating a foamed material on a container, including preparing a coating material by heat-blending or kneading a solid thermoplastic binder with a solid thermo-expandable powder consisting of a plurality of solid thermo-expandable microcapsules. US 20020142106 is directed to a method for applying decoration to a support including depositing an ink solution on the support, wherein the ink solution contains thermally expandable particles, and a microwave device is used to the thermally expandable particles, contained in the ink solution, expand.
One of the challenges facing manufacturers of articles having three-dimensional decorations on plastic, metal, and other non-fibrous surfaces is ensuring the lasting durability of the decorations, under the conditions of making, transporting, and using the article. The fact that fibrous materials have pores and typically possess good capillary properties makes the fibrous materials are particularly well suited for receiving and securely retaining three-dimensional patterns applied thereto. Non-fibrous materials, on the other hand, do not have fibers and therefore are poorly suited for this purpose since the non-fibrous materials cannot exhibit good fiber-capillary properties. The retention and durability of a three-dimensional pattern applied to a non-fibrous substrate is a particularly challenging task for manufacturers of articles that have non-planar shape of the external surface (such as, e.g., bottles, having a generally concave shape) and that often experience surface deformation and harsh contact with other similar articles and/or items (such, e.g., as packaging crates) during handling, shipping, and ultimate use by a consumer.
The present invention is directed to a process for making a stable and durable three-dimensional pattern on a non-fibrous substrate.